The proposal is to study certain neurophysiological aspects of amblyopia in an animal model using monkeys. Single unit recordings will be made in the striate cortex and lateral geniculate nucleus. Units will be characterized by classic receptive field terminology, X/Y spatial summation classification, sustained/transient classification, and spatial frequency response as measured by the contrast sensitivity. Recordings in six-month old animals will be compared among normal controls and animals which at a few weeks of age have either undergone an optical blur of one or both eyes or had a strabismus surgically induced. Particular attention will be directed to the transfer of spatial frequency information to the cortex.